OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Question On Scott Bonnar Cylinder Mowers Scott Bonnar Model 45 - Routine Maintenance

Hi to All,
The time has come to do some routine maintenance on my Scotty 45. I needed a raised work area to put my mower on, to make it easier to work on,
so I fabricated one quickly using 2 saw horses with a suitable piece of 5 ply fastened with screws to the horses.

I made a ramp from a piece of timber to get the Scotty on top of my new "table" and, as I couldn't lift it up...I drove it up the ramp under its own power. I used a couple of old right-angle brackets screwed to the front edge of the "table" to stop the machine rolling forward and a wooden wedge under the rear roller to stop it rolling backwards.
Here's a pic...


I wanted to dress the bed-knife blade with the "Bed Knife Buddy" and to do so, you have to lay the mower down backwards, so the first thing to do is drain the oil. This is to stop the oil going places it shouldn't go inside the engine.

To do that successfully, you should run the engine up to operating temperature to warm the oil, shut it down; turn off the fuel, lay it down backwards and remove the oil drain plug and the oil filler plug....as soon as it has finished draining, replace the drain plug but NOT the filler plug...
This will remind you to place new oil in later, when you have finished the job.

Whilst it is laying backwards it is easy to check the alignment of the bedknife and soleplate with the rear and front rollers using the alignment tool....Here's a pic of the machine laying back exposing the bedknife easily...


Here's one checking alignment ...


Here's a couple of pics using the "Bed knife buddy"and the tool itself....




Once the bedknife blade is dressed its time to check the chains and sprockets....remove the chain-case cover and examine all sprockets and chains for wear and tension, and adjust if necessary....oil or grease well all the moving parts and clean and replace the cover. Place the machine back in upright position and fill with the correct oil....I use Honda 4 stroke oil...see here..


Next on the list is to grab the oil can and oil all the oiling points...clutch thrust pad, and clutch cone oil hole and if necessary adjust the clutch so as moving the clutch lever to the upright position, releases the cutter clutch completely (ie. the cylinder reel doesn't move with the engine running at idle).
For this I have made a handy tool...grab an old 7/16" ring spanner and grind a slot in the top edge carefully with the spanner secured in a vice using an angle grinder to do the job. Don't forget your safety glasses. This makes an open end ring spanner that can fit over the screw threads of the cylinder reel adjusters and the clutch lever adjustment lock nut which is located inside the lever actuating arm. Please see pics...




Lastly, but most importantly, go over the machine thoroughly checking all nuts and bolts for security.

Well, that's it, you're done!! Carefully lower the machine to the ground and give the starter rope a few strong pulls (ignition off, of course) to help distribute the new oil up the cylinder walls...turn on ignition and give the engine a run briefly.
Happy mowing....